This blog post will explain how to use FFMPEG to create a video with a still image and music playing in the background. In order to accomplish that task an image and mp3 have to be used as input files. The -loop flag will loop the image over the song in the video. The -r flag will set the framerate of the video. The -c:a copy flag will copy the audio to the video file. The -shortest flag will end encoding of the video once the song is over.

ffmpeg -loop 1 -r 1 -i image.png -i track.mp3 -c:a copy -shortest video.mp4